The future of current WWE World Heavyweight Champion Brock Lesnar is going to be one of the biggest stories in WWE this year. As we know, his deal with WWE is set to expire at the end of March right after WrestleMania 31 and the Raw that will follow it. Then what? We don't know. Lesnar is going to be a free agent. He will have to decide on if he wants to keep being a professional wrestler or go back to Mixed Martial Arts fighting. Another option is that he could simply retire. Lesnar's going to turn 38 years old this year and he's got millions of dollars in the bank, so as long as he saved his money he doesn't have to work again. However, the competitive fire seems to be there. It would be a surprise if he stopped working this year. The feeling among people that follow the wrestling business closely is that Lesnar is going to leave WWE and head back to the Ultimate Fighting Championship. As somebody that follows WWE more than UFC, my feeling is that he's gone from WWE and headed to UFC. Is that the best move for him? I'm not sure about that. I'm even less sure about it after witnessing his incredible performance in the WWE Title match at the Royal Rumble. Lesnar is going to have a big decision to make in a few months. Perhaps he already knows where he's going after his WWE commitments are done at the end of March. Don't expect to hear it from him because he's such a private guy. Until then, all we can do is speculate and try to figure out what "The Beast" may be thinking. Here's a look at five reasons why Lesnar should stay right where he is in WWE and also five reasons why he's likely to leave.